# Payment Gateway Implementation Documentation

## Overview
This document describes the comprehensive payment gateway system implemented for the Laravel Grocery SaaS platform, allowing tenants to purchase subscription plans through multiple payment methods.

## Implementation Date
**Date**: 2026-01-31 12:25 AM

## Features Implemented

### 1. Multiple Payment Gateway Support
- **Stripe** - Credit/Debit card payments (Online)
- **SSLCommerz** - Local payment gateway (Online) 
- **bKash** - Mobile banking (Manual verification)
- **Nagad** - Mobile banking (Manual verification)
- **Rocket** - Mobile banking (Manual verification)

### 2. Admin Payment Settings Management
- Configure payment gateway credentials
- Enable/disable payment methods
- Sandbox/Live mode switching
- Manual payment method setup

### 3. Tenant Subscription Purchase Flow
- Plan selection with payment method choice
- Real-time payment processing
- Manual payment instructions
- Payment verification system

### 4. Payment Processing Service
- Unified payment service interface
- Gateway-specific implementations
- Error handling and logging
- Refund processing capabilities

## Architecture

### Core Components

#### 1. PaymentService (`app/Services/PaymentService.php`)
```php
class PaymentService
{
    // Main payment processing service
    // Supports multiple gateways
    // Handles payment verification
    // Manages refunds
}
```

#### 2. PaymentController (`app/Http/Controllers/PaymentController.php`)
```php
class PaymentController
{
    // Admin payment settings management
    // Payment processing endpoints
    // Refund functionality
}
```

#### 3. Tenant SubscriptionController (`app/Http/Controllers/Tenant/SubscriptionController.php`)
```php
class SubscriptionController
{
    // Tenant subscription purchase
    // Payment gateway integration
    // Payment instructions display
}
```

### Database Schema Updates

#### Subscriptions Table
Added payment-related fields:
- `payment_gateway` - Payment method used
- `transaction_id` - Gateway transaction ID
- `amount` - Payment amount
- `currency` - Payment currency
- `payment_status` - Payment status
- `verified_at` - Payment verification timestamp
- `refunded_at` - Refund timestamp
- `refund_reason` - Refund reason
- `refund_amount` - Refunded amount
- `refund_id` - Refund transaction ID

## Payment Gateway Configuration

### 1. Stripe Configuration
```php
AppSetting::set('payment_gateway', 'stripe');
AppSetting::set('payment_key', 'pk_test_...');
AppSetting::set('payment_secret', 'sk_test_...');
AppSetting::set('stripe_sandbox', '1');
```

### 2. SSLCommerz Configuration
```php
AppSetting::set('sslcommerz_store_id', 'store_id');
AppSetting::set('sslcommerz_store_password', 'password');
AppSetting::set('sslcommerz_sandbox', '1');
```

### 3. Manual Payment Methods
```php
AppSetting::set('enable_bkash_manual', '1');
AppSetting::set('bkash_number', '+8801XXXXXXXXX');
AppSetting::set('bkash_type', 'personal');
```

## Payment Flow

### 1. Online Payments (Stripe/SSLCommerz)
1. Tenant selects plan and payment method
2. PaymentService creates payment intent/redirect
3. Tenant completes payment on gateway
4. Gateway sends callback/webhook
5. System verifies and activates subscription

### 2. Manual Payments (bKash/Nagad/Rocket)
1. Tenant selects plan and manual payment method
2. System generates transaction ID
3. Display payment instructions
4. Tenant makes payment manually
5. Admin verifies payment and activates subscription

## API Endpoints

### Admin Routes
- `GET /admin/payment` - Payment settings page
- `PUT /admin/payment` - Update payment settings
- `POST /admin/subscriptions/{id}/refund` - Process refund

### Tenant Routes
- `POST /tenant/subscriptions/{plan}/purchase` - Purchase subscription
- `GET /tenant/payment/success` - Payment success callback
- `POST /tenant/payment/callback` - Payment webhook

### Public Routes
- `GET /payment/success` - Generic payment success
- `POST /payment/callback` - Generic payment callback

## Testing Results

### Payment Gateway Detection
✅ **Active Gateways Detected:**
- Stripe (card) - Sandbox mode
- SSLCommerz (gateway) - Sandbox mode  
- bKash (manual) - Enabled

### Payment Processing Tests
✅ **Stripe Payment:**
- Transaction ID: `pi_3SvMVkHJTt4cpFqf0Q252TwI`
- Status: `requires_payment_method`
- Amount: `$10.00`
- Client Secret generated successfully

✅ **bKash Manual Payment:**
- Transaction ID: `BKASH_697cf92d4be94`
- Status: `pending_manual_verification`
- Amount: `15.00 BDT`
- Instructions generated successfully

## Security Features

### 1. Payment Data Protection
- All sensitive data encrypted in transit
- API keys stored securely in database
- Sandbox mode for testing

### 2. Transaction Integrity
- Unique transaction IDs
- Payment verification system
- Audit logging for all transactions

### 3. Refund Protection
- Admin-only refund access
- Refund reason tracking
- Partial refund support

## Frontend Integration

### 1. Admin Payment Settings
- `/resources/views/admin/payment/index.blade.php`
- Gateway configuration interface
- Real-time gateway status display

### 2. Tenant Subscription
- `/resources/views/tenant/subscription/index.blade.php`
- Payment method selection
- Gateway availability checking

### 3. Payment Instructions
- `/resources/views/tenant/subscription/payment-instructions.blade.php`
- Manual payment steps
- Contact support information

## Error Handling

### 1. Payment Processing Errors
- Comprehensive logging
- User-friendly error messages
- Automatic retry mechanisms

### 2. Gateway Communication Errors
- Fallback mechanisms
- Error notification system
- Manual verification options

## Future Enhancements

### 1. Additional Gateways
- PayPal integration
- Local bank transfers
- Cryptocurrency payments

### 2. Advanced Features
- Subscription management
- Automated billing
- Payment analytics

### 3. Security Improvements
- 3D Secure integration
- Fraud detection
- PCI compliance

## Troubleshooting

### Common Issues

#### 1. Stripe Payment Intent Error
**Error**: "You cannot enable `automatic_payment_methods` and specify `payment_method_types`"
**Solution**: Removed `automatic_payment_methods` parameter

#### 2. Gateway Not Active
**Error**: "Payment gateways not configured"
**Solution**: Configure payment settings in admin panel

#### 3. Manual Payment Verification
**Error**: "Payment pending verification"
**Solution**: Admin must manually verify payment in admin panel

## Conclusion

The payment gateway system has been successfully implemented with:
- ✅ Multiple payment gateway support
- ✅ Admin configuration interface
- ✅ Tenant purchase flow
- ✅ Payment verification system
- ✅ Refund processing
- ✅ Comprehensive error handling
- ✅ Security measures

The system is now ready for production use with proper payment gateway configuration and testing.
